{"id":718,"date":"2023-03-23T21:50:23","date_gmt":"2023-03-23T13:50:23","guid":{"rendered":""},"modified":"2023-03-23T21:50:23","modified_gmt":"2023-03-23T13:50:23","slug":"Java extends\u5173\u952e\u8bcd","status":"publish","type":"post","link":"https:\/\/bianchenghao6.com\/718.html","title":{"rendered":"Java extends\u5173\u952e\u8bcd"},"content":{"rendered":"


\n <\/head>
\n <\/p>\n

\n

Java extends\u5173\u952e\u8bcd<\/h1>\n<\/p><\/div>\n
\n Java\u7ee7\u627f<\/strong>\u662f\u4e00\u79cd\u673a\u5236\uff0c\u5176\u4e2d\u4e00\u4e2a\u5bf9\u8c61\u83b7\u53d6\u7236\u5bf9\u8c61\u7684\u6240\u6709\u5c5e\u6027\u548c\u884c\u4e3a\u3002\u5b83\u662fOOPs(\u9762\u5411\u5bf9\u8c61\u7684\u7f16\u7a0b\u7cfb\u7edf)\u7684\u91cd\u8981\u7ec4\u6210\u90e8\u5206\u3002\n <\/div>\n
\n Java\u7ee7\u627f\u7684\u601d\u60f3\u662f\u53ef\u4ee5\u521b\u5efa\u65b0\u7684\u5efa\u7acb\u5728\u73b0\u6709\u7c7b\u4e4b\u4e0a\u7684\u7c7b\u3002\u4ece\u73b0\u6709\u7c7b\u7ee7\u627f\u65f6\uff0c\u53ef\u4ee5\u91cd\u7528\u7236\u7c7b\u7684\u65b9\u6cd5\u548c\u5b57\u6bb5\u3002\u6b64\u5916\uff0c\u60a8\u8fd8\u53ef\u4ee5\u5728\u5f53\u524d\u7c7b\u4e2d\u6dfb\u52a0\u65b0\u7684\u65b9\u6cd5\u548c\u5b57\u6bb5\u3002\n <\/div>\n
\n \u7ee7\u627f\u8868\u793a
\n IS-A\u5173\u7cfb<\/strong>\uff0c\u4e5f\u79f0\u4e3a
\n parent-child <\/em>\u5173\u7cfb\u3002\n <\/div>\n

\u4e3a\u4ec0\u4e48\u5728Java\u4e2d\u4f7f\u7528\u7ee7\u627f<\/h3>\n

\u5bf9\u4e8e\u65b9\u6cd5\u8986\u76d6(\u56e0\u6b64\u53ef\u4ee5\u5b9e\u73b0\u8fd0\u884c\u65f6\u591a\u6001) \u3002<\/span>
\n \u7528\u4e8e\u4ee3\u7801\u53ef\u91cd\u7528\u6027\u3002<\/span> <\/p>\n

\u7ee7\u627f\u4e2d\u4f7f\u7528\u7684\u672f\u8bed<\/h3>\n

\u7c7b: <\/strong>\u7c7b\u662f\u5177\u6709\u5171\u540c\u5c5e\u6027\u7684\u4e00\u7ec4\u5bf9\u8c61\u3002\u5b83\u662f\u7528\u4e8e\u521b\u5efa\u5bf9\u8c61\u7684\u6a21\u677f\u6216\u84dd\u56fe\u3002<\/span>
\n \u5b50\u7c7b: <\/strong>\u5b50\u7c7b\u662f\u7ee7\u627f\u5176\u4ed6\u7c7b\u7684\u7c7b\u3002\u4e5f\u79f0\u4e3a\u6d3e\u751f\u7c7b\uff0c\u6269\u5c55\u7c7b\u6216\u5b50\u7c7b\u3002 <\/span>
\n \u7236\u7c7b: <\/strong>: \u8d85\u7ea7\u7c7b\u662f\u5b50\u7c7b\u4ece\u4e2d\u7ee7\u627f\u8981\u7d20\u7684\u7c7b\u3002\u4e5f\u79f0\u4e3a\u57fa\u7c7b\u6216\u7236\u7c7b\u3002<\/span>
\n \u53ef\u91cd\u7528\u6027<\/strong>: \u987e\u540d\u601d\u4e49\uff0c\u53ef\u91cd\u7528\u6027\u662f\u4e00\u79cd\u673a\u5236\uff0c\u53ef\u5e2e\u52a9\u60a8\u5728\u521b\u5efa\u65b0\u7c7b\u65f6\u91cd\u7528\u73b0\u6709\u7c7b\u7684\u5b57\u6bb5\u548c\u65b9\u6cd5\u3002\u60a8\u53ef\u4ee5\u4f7f\u7528\u4e0a\u4e00\u7c7b\u4e2d\u5df2\u5b9a\u4e49\u7684\u76f8\u540c\u5b57\u6bb5\u548c\u65b9\u6cd5\u3002 <\/span> <\/p>\n

Java\u7ee7\u627f\u7684\u8bed\u6cd5<\/h3>\n
\n
 class Subclass-name extends <\/span>Superclass-name{
 \/\/methods and fields}
 <\/span><\/code><\/pre>\n<\/p><\/div>\n
\n    extends\u5173\u952e\u5b57<\/strong>\u8868\u793a\u60a8\u6b63\u5728\u521b\u5efa\u4e00\u4e2a\u4ece\u73b0\u6709\u7c7b\u6d3e\u751f\u7684\u65b0\u7c7b\u3002 \"\u6269\u5c55\"\u7684\u610f\u601d\u662f\u589e\u52a0\u529f\u80fd\u3002\n  <\/div>\n
\n    \u5728Java\u7684\u672f\u8bed\u4e2d\uff0c\u88ab\u7ee7\u627f\u7684\u7c7b\u79f0\u4e3a\u7236\u7c7b\u6216\u8d85\u7c7b\uff0c\u800c\u65b0\u7c7b\u79f0\u4e3a\u5b50\u7ea7\u6216\u5b50\u7c7b\u3002\n  <\/div>\n
\n
 Java\u7ee7\u627f\u793a\u4f8b<\/h3>\n
  Java extends\u5173\u952e\u8bcd_https:\/\/bianchenghao6.com_\u3010Java \u57fa\u7840\u6559\u7a0b\u3011_\u7b2c1\u5f20 <\/p>\n
\n    \u4e0a\u56fe\u4e2d\uff0cProgrammer\u662f\u5b50\u7c7b\uff0c\u800cEmployee\u662f\u8d85\u7c7b\u3002\u8fd9\u4e24\u4e2a\u7c7b\u522b\u4e4b\u95f4\u7684\u5173\u7cfb\u662f
\n   \u7a0b\u5e8f\u5458IS-A\u96c7\u5458<\/strong>\u3002\u8fd9\u610f\u5473\u7740\u7a0b\u5e8f\u5458\u662f\u96c7\u5458\u7684\u4e00\u79cd\u3002\n  <\/div>\n
\n
 class Employee{
     float<\/span> salary=40000;
 }
 class Programmer extends <\/span>Employee{
     int bonus=10000;
     public <\/span>static void <\/span>main(String args[]){
         Programmer p=new Programmer();
         System.out.println<\/span><\/span>(\"Programmer salary is:\"<\/span>+p.salary);
         System.out.println<\/span><\/span>(\"Bonus of Programmer is:\"<\/span>+p.bonus);
     }
 }
 <\/span><\/code><\/pre>\n<\/p><\/div>\n
\n
\n
Programmer salary is:40000.0 \n
 Bonus of programmer is:10000<\/code><\/pre>\n<\/p><\/div>\n<\/p><\/div>\n
\n    \u5728\u4e0a\u9762\u7684\u793a\u4f8b\u4e2d\uff0cProgrammer\u5bf9\u8c61\u53ef\u4ee5\u8bbf\u95ee\u81ea\u5df1\u7684\u7c7b\u4ee5\u53caEmployee\u7c7b\u7684\u5b57\u6bb5\uff0c\u5373\u4ee3\u7801\u53ef\u91cd\u7528\u6027\u3002\n  <\/div>\n
\n
    <\/p>\n
 java\u4e2d\u7684\u7ee7\u627f\u7c7b\u578b<\/h2>\n
\n    \u5728\u7c7b\u7684\u57fa\u7840\u4e0a\uff0cjava\u4e2d\u53ef\u4ee5\u5b58\u5728\u4e09\u79cd\u7ee7\u627f\u7c7b\u578b: \u5355\u5c42\uff0c\u591a\u5c42\u548c\u5206\u5c42\u3002\n  <\/div>\n
\n    \u5728Java\u7f16\u7a0b\u4e2d\uff0c\u4ec5\u901a\u8fc7\u63a5\u53e3\u652f\u6301\u591a\u91cd\u7ee7\u627f\u548c\u6df7\u5408\u7ee7\u627f\u3002\n  <\/div>\n
  Java extends\u5173\u952e\u8bcd_https:\/\/bianchenghao6.com_\u3010Java \u57fa\u7840\u6559\u7a0b\u3011_\u7b2c2\u5f20 <\/p>\n
\n
\n    \u6ce8\u610f: <\/span> Java\u901a\u8fc7\u7c7b\u4e0d\u652f\u6301\u591a\u91cd\u7ee7\u627f\u3002\n   <\/div>\n<\/h3>\n
\n    \u5f53\u4e00\u4e2a\u7c7b\u7ee7\u627f\u591a\u4e2a\u7c7b\u65f6\uff0c\u79f0\u200b\u200b\u4e3a\u591a\u91cd\u7ee7\u627f\u3002\u4f8b\u5982:\n  <\/div>\n
  Java extends\u5173\u952e\u8bcd_https:\/\/bianchenghao6.com_\u3010Java \u57fa\u7840\u6559\u7a0b\u3011_\u7b2c3\u5f20 <\/p>\n
\n
\u5355\u4e2a\u7ee7\u627f\u793a\u4f8b<\/h2>\n
\n    \u5f53\u4e00\u4e2a\u7c7b\u7ee7\u627f\u53e6\u4e00\u4e2a\u7c7b\u65f6\uff0c\u79f0\u200b\u200b\u4e3a
\n   \u5355\u4e2a\u7ee7\u627f<\/em>\u3002\u5728\u4e0b\u9762\u7ed9\u51fa\u7684\u793a\u4f8b\u4e2d\uff0cDog\u7c7b\u7ee7\u627f\u4e86Animal\u7c7b\uff0c\u56e0\u6b64\u5b58\u5728\u5355\u4e2a\u7ee7\u627f\u3002\n  <\/div>\n
\n    \u6587\u4ef6: TestInheritance.java\n  <\/div>\n
\n
 class Animal{
     void eat(){
         System.out.println<\/span><\/span>(\"eating...\"<\/span>);
     }
 }
 class Dog extends <\/span>Animal{
     void bark(){
         System.out.println<\/span><\/span>(\"barking...\"<\/span>);
     }
 }
 class TestInheritance{
     public <\/span>static void <\/span>main(String args[]){
         Dog d=new Dog();
         d.bark<\/span>();
         d.eat<\/span>();
     }
 }
 <\/span><\/code><\/pre>\n<\/p><\/div>\n
\n    \u8f93\u51fa:\n  <\/div>\n
\n
\n
barking... \n
 eating...<\/code><\/pre>\n<\/p><\/div>\n<\/p><\/div>\n
\u591a\u7ea7\u7ee7\u627f\u793a\u4f8b<\/h2>\n
\n    \u5982\u679c\u5b58\u5728\u7ee7\u627f\u94fe\uff0c\u5219\u79f0\u4e3a
\n   \u591a\u7ea7\u7ee7\u627f<\/em>\u3002\u5982\u4e0b\u9762\u7684\u793a\u4f8b\u6240\u793a\uff0cBabyDog\u7c7b\u7ee7\u627f\u4e86Dog\u7c7b\uff0c\u800cDog\u7c7b\u53c8\u7ee7\u627f\u4e86Animal\u7c7b\uff0c\u56e0\u6b64\u5b58\u5728\u591a\u7ea7\u7ee7\u627f\u3002\n  <\/div>\n
\n    \u6587\u4ef6: TestInheritance2.java\n  <\/div>\n
\n
 class Animal{
     void eat(){
         System.out.println<\/span><\/span>(\"eating...\"<\/span>);
     }
 }
 class Dog extends <\/span>Animal{
     void bark(){
         System.out.println<\/span><\/span>(\"barking...\"<\/span>);
     }
 }
 class BabyDog extends <\/span>Dog{
     void weep(){
         System.out.println<\/span><\/span>(\"weeping...\"<\/span>);
     }
 }
 class TestInheritance2{
     public <\/span>static void <\/span>main(String args[]){
         BabyDog d=new BabyDog();
         d.weep<\/span>();
         d.bark<\/span>();
         d.eat<\/span>();
     }
 }
 <\/span><\/code><\/pre>\n<\/p><\/div>\n
\n    \u8f93\u51fa:\n  <\/div>\n
\n
\n
weeping... \n
 barking... \n
 eating...<\/code><\/pre>\n<\/p><\/div>\n<\/p><\/div>\n
\u5206\u5c42\u7ee7\u627f\u793a\u4f8b<\/h2>\n
\n    \u5f53\u4e24\u4e2a\u6216\u591a\u4e2a\u7c7b\u7ee7\u627f\u5355\u4e2a\u7c7b\u65f6\uff0c\u79f0\u200b\u200b\u4e3a
\n   \u5206\u5c42\u7ee7\u627f<\/em>\u3002\u5728\u4e0b\u9762\u7ed9\u51fa\u7684\u793a\u4f8b\u4e2d\uff0cDog\u548cCat\u7c7b\u7ee7\u627f\u4e86Animal\u7c7b\uff0c\u56e0\u6b64\u5b58\u5728\u5c42\u6b21\u7ed3\u6784\u7ee7\u627f\u3002\n  <\/div>\n
\n    \u6587\u4ef6: TestInheritance3.java\n  <\/div>\n
\n
 class Animal{
     void eat(){
         System.out.println<\/span><\/span>(\"eating...\"<\/span>);
     }
 }
 class Dog extends <\/span>Animal{
     void bark(){
         System.out.println<\/span><\/span>(\"barking...\"<\/span>);
     }
 }
 class Cat extends <\/span>Animal{
     void meow(){
         System.out.println<\/span><\/span>(\"meowing...\"<\/span>);
     }
 }
 class TestInheritance3{
     public <\/span>static void <\/span>main(String args[]){
         cat <\/span>c=new Cat();
         c.meow<\/span>();
         c.eat<\/span>();
         \/\/c.bark<\/span>();
     \/\/C.T.Error}
 }
 <\/span><\/code><\/pre>\n<\/p><\/div>\n
\n    \u8f93\u51fa:\n  <\/div>\n
\n
\n
meowing... \n
 eating...<\/code><\/pre>\n<\/p><\/div>\n<\/p><\/div>\n
\n
    <\/p>\n
 Q)\u4e3a\u4ec0\u4e48Java\u4e0d\u652f\u6301\u591a\u91cd\u7ee7\u627f\uff1f<\/h2>\n
\n    \u4e3a\u964d\u4f4e\u590d\u6742\u6027\u5e76\u7b80\u5316\u8bed\u8a00\uff0c Java\u4e0d\u652f\u6301\u591a\u91cd\u7ee7\u627f\u3002\n  <\/div>\n
\n    \u8003\u8651\u4e00\u4e2a\u573a\u666f\uff0c\u5176\u4e2dA\uff0cB\u548cC\u662f\u4e09\u4e2a\u7c7b\u3002 C\u7c7b\u7ee7\u627fA\u548cB\u7c7b\u3002\u5982\u679cA\u7c7b\u548cB\u7c7b\u5177\u6709\u76f8\u540c\u7684\u65b9\u6cd5\uff0c\u5e76\u4e14\u60a8\u4ece\u5b50\u7c7b\u5bf9\u8c61\u8c03\u7528\u5b83\uff0c\u5219\u6a21\u68f1\u4e24\u53ef\u5730\u8c03\u7528A\u7c7b\u6216B\u7c7b\u7684\u65b9\u6cd5\u3002\n  <\/div>\n
\n    \u7531\u4e8e\u7f16\u8bd1\u65f6\u9519\u8bef\u6bd4\u8fd0\u884c\u65f6\u9519\u8bef\u8981\u597d\uff0c\u5982\u679c\u60a8\u7ee7\u627f2\u4e2a\u7c7b\uff0c\u5219Java\u4f1a\u51fa\u73b0\u7f16\u8bd1\u65f6\u9519\u8bef\u3002\u56e0\u6b64\uff0c\u65e0\u8bba\u65b9\u6cd5\u76f8\u540c\u8fd8\u662f\u4e0d\u540c\uff0c\u90fd\u4f1a\u51fa\u73b0\u7f16\u8bd1\u65f6\u9519\u8bef\u3002\n  <\/div>\n
\n
 class A{
     void msg(){
         System.out.println<\/span><\/span>(\"Hello\"<\/span>);
     }
 }
 class B{
     void msg(){
         System.out.println<\/span><\/span>(\"Welcome\"<\/span>);
     }
 }
 class C extends <\/span>A,B{
     \/\/suppose if <\/span>it were public <\/span>static void <\/span>main(String args[]){
         C obj=new C();
         obj.msg<\/span>();
     \/\/Now which msg() method would be invoked?}
 }
 <\/span><\/code><\/pre>\n<\/p><\/div>\n
\n
\n
Compile Time Error<\/code><\/pre>\n<\/p><\/div>\n<\/p><\/div>\n
 <\/body>
\n<\/html><\/p>\n","protected":false},"excerpt":{"rendered":"Java extends\u5173\u952e\u8bcdzh-cn","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[111],"tags":[],"class_list":["post-718","post","type-post","status-publish","format-standard","hentry","category-java-jichu"],"_links":{"self":[{"href":"https:\/\/bianchenghao6.com\/wp-json\/wp\/v2\/posts\/718"}],"collection":[{"href":"https:\/\/bianchenghao6.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bianchenghao6.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bianchenghao6.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/bianchenghao6.com\/wp-json\/wp\/v2\/comments?post=718"}],"version-history":[{"count":0,"href":"https:\/\/bianchenghao6.com\/wp-json\/wp\/v2\/posts\/718\/revisions"}],"wp:attachment":[{"href":"https:\/\/bianchenghao6.com\/wp-json\/wp\/v2\/media?parent=718"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bianchenghao6.com\/wp-json\/wp\/v2\/categories?post=718"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bianchenghao6.com\/wp-json\/wp\/v2\/tags?post=718"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}